I've finally decided to get back to my experiments with the Doom 3DO source code and actually make an official first release of my port. I have set a deadline till the 25th aniversary of Doom (which is tomorrow but couldn't wait till tomorrow that is Monday and I am working

It's time to just release what I have so far, there are some additional gimmicks and stuff inside, little performance/quality settings which slightly improve speed but not as much as I'd wish (I leave this for the next releases). But it's good time to release what I have so far so that I get some feedback and plan for the future.

p.s. I don't give ISO on my site, but decided to give a zip file with compiled binary executable (plus two additional files) and the tools and instructions necessary to extract files from the original commercial CD or ISO that you may own, copy my files, write it back to ISO, and also use the second tool to properly encrypt it so that it runs. Kinda like how modern Doom port do, giving the binary files but never the full data. Might be a stretch since it's an old console nobody will care, but I just wanted to be consistent and legit here, at least on my site. Now, I don't know where people upload full ISOs modded by the community and what is legit and what's not, but if one builds an ISO from my port and wishes to upload at different places, I'm fine with that. Just let me know what you think.

Awesome work! And your idea not to recompile a rezfile for mods is very cool! But also a time consuming to make it.

I was extracting the ISO and looked that few resources like the sound fx are not in the Rez. Then I thought "Cool, someone could alter the sounds without the need of recompiling, so they can make a doom with PSX sound effects for example, as long as I see how to convert to aiff". Then it hit me: what if they extract the CD files, copy a special folder MODS for example with inside SFX, MUSIC, MAPS,. and I just parse them, as the code already parses the sound fx early? A user could throw for example MAP01.WAD inside MAPS and I would parse it. Or I could organize it into MODS/name_of_the_mod and let a menu select between which mod to play. That's just an idea I am excited about and since I can work a lot on the code, I might do at some point. I can start from simple things like what file function I can use to traverse a directory and parse files, I could just throw a PSX folder inside SOUNDS with my AIFF from PSX sound effects (if I can find how to extract and convert) and make it selectable from the menu.

It's a problem with the additional sounds I mentioned earlier. With big quantity of them more often CD reading occures. It freezes the gameplay.
I wrote this in a comments below your video:
Music is streamed from CD, but sound effects are all loaded during startup. That's why I stucked at the adding new sound effects. Only few new sounds doesn't affect the perfomance during gameplay. Maybe I should split sounds effects for different levels and load them only during level loading. Not sure...

It's a problem with the additional sounds I mentioned earlier. With big quantity of them more often CD reading occures. It freezes the gameplay.
I wrote this in a comments below your video:
Music is streamed from CD, but sound effects are all loaded during startup. That's why I stucked at the adding new sound effects. Only few new sounds doesn't affect the perfomance during gameplay. Maybe I should split sounds effects for different levels and load them only during level loading. Not sure...

Yes, I noticed the sound effects are an exception, they are loaded earlier in threedo.c
If I have to do this, I'll have to unload what is there, and reload another set of soundeffects, if for example I have a second folder with PSX sound effects. I already had this in my mind if I will code this feature, to release those sound resources before loading other sets.
But if there are more sfx like from Doom 2, then the approach of loading things per level maybe would work and that would be hard to do though, one would have to traverse every "thing" in the level, find which monsters and other things exist, or something. I am not even thinking doing this now. I am only thinking what if a modder supplies a second folder with the exact same number of sound effects with the same exact names but on a second folder (and hopefully he keeps sound effect size similar, else one could upload big lengthy sounds that I cannot fit).

I also noticed at some point, when I was making a dummy static array to check something with memory, as I was approaching bigger sizes, but still not crashing E1M1, I started getting those freeze you seemed to be getting in the past with additional monsters. Maybe that will be a way for me to create this bug intentionally and test it again, not sure where or how. Maybe it's more release and alloc of memory happening frequently.

Just have a look at the OptiDoom page.
A zip file with a more easy automated process than before is provided. There are necessary files, command line tools and a batch file inside. You have to provide the commercial Doom ISO yourself, rename it as doom.iso and throw inside, run the batch file, and optidoom.iso will come back if everything is correct.

Are you just tweaking the engine or do you plan on rebuilding it for speed?

What came after the Jaguar was the PS1 which for all it's greatness, ushered in corporate development and with it the bleached, repetitive, bland titles which for the most part we're still playing today. - David Wightman